Determination of Instrumental Vaginal Delivery and Associated Maternal and Neonatal Outcomes in Term Pregnancies with Elevated Estimated Fetal Weight

Abstract

Objective: To determine the frequency of instrumental vaginal delivery and describe selected maternal and neonatal outcomes among term pregnancies with an estimated fetal weight of 3500–4500 g.

Methodology: This descriptive cross-sectional study was conducted at the Department of Obstetrics and Gynaecology, MCH, PIMS, Islamabad from Mar-June 2026. A total of 384 women aged 18–40 years with singleton term pregnancies (37–42 weeks) and ultrasound-estimated fetal weight of 3500–4500 g were enrolled using consecutive sampling. Instrumental vaginal delivery was defined as delivery assisted by vacuum or forceps. Maternal and neonatal characteristics, duration of the second stage of labour, maternal hemorrhage, NICU admission, and Apgar scores were recorded. Data were analyzed using SPSS version 22.0. The Chi-square test was used for categorical comparisons, with p<0.05 considered statistically significant.

Results: Among 384 women, 34 (8.9%) underwent instrumental vaginal delivery, including 21 (61.8%) vacuum and 13 (38.2%) forceps deliveries. Instrumental delivery was more frequent among primiparous women than multiparous women (11.8% vs. 5.8%, p=0.027). A prolonged second stage was documented in 27 (79.4%) instrumental deliveries. Maternal hemorrhage occurred in 8 (23.5%) instrumental deliveries, while 10 (29.4%) neonates were admitted to the NICU. NICU admission was significantly associated with instrumental delivery (29.4% vs. 7.7%, p=0.019). Instrumental delivery increased with EFW, reaching 25.0% among pregnancies with EFW of 4100–4500 g; however, this trend was not statistically significant (p=0.064).

Conclusion: Instrumental vaginal delivery was performed in 8.9% of term pregnancies with an estimated fetal weight of 3500–4500 g, with vacuum used more frequently than forceps. Its occurrence was significantly associated with parity, while NICU admission was significantly more frequent among instrumental deliveries. Larger prospective studies with comprehensive maternal and neonatal outcome assessment are needed to further evaluate operative vaginal delivery in pregnancies with elevated estimated fetal weight.